Environment

For energy and greenhouse gas management, UMC has recently formulated various environmental protection objectives for various phases and dimensions along with actual implementation plans.

UMC engages with stakeholders to gather feedback and support the implementation of ours Net Zero transition plan.

UMC established its GHG inventory standard mechanism in accordance with inventory guidelines defined by domestic and international organizations such as the ISO14064-1:2018, World Resources Institute’s Greenhouse Gas Protocol and GHG Inventory Guidance in Taiwan. Since 2006, the Company has inventoried the GHG emissions of all fabs annually to verify the effectiveness of reduction measures. Furthermore, UMC’s all consolidated subsidiaries introduced the GHG inventory mechanism and conduct third-party verification to fully determine the status of GHG emissions.

Through carbon footprint and GHG inventories, the Company learned that the main GHG sources are the fluorinated greenhouse gases (F-GHGs) used in the manufacturing process in Scope 1, and from purchased electricity in Scope 2. These emissions account for about 95% of UMC overall GHG emissions. Therefore, GHG reduction of both F-GHGs and purchased electricity have become the priority for UMC. Through low-carbon production processes, UMC produces products with relatively low carbon footprints. All UMC facilities have implemented reduction plans, and all products use low-carbon processes.

Additionally, UMC continues to develop low-power consumption products through the research and development of energy-saving innovative process platforms, which helps avoid carbon emissions during the product end-use phase.

In 2025, based on actual production capacity, UMC Group's Scope 1 and Scope 2 greenhouse gas emissions presented an absolute reduction of 37% as compared to the base year (2020). Even under full capacity scenarios, a reduction of 24% is still achievable, demonstrating the Group's commitment to decarbonization regardless of capacity fluctuations, and making a tangible contribution to global greenhouse gas reduction.

UMC established the F-GHGs Reduction Taskforce in 1999 to promote GHG reduction. Moreover, the company set GHG reduction goals for the various phases of the program, and has continually conducted reduction measures such as installing high performance local scrubbers for F-GHGs in all new equipment, and utilizing NF₃ gases in new CVD equipment to keep emission intensity in a downward trend.

In addition, based on the Electronic Product Environmental Assessment Tool (EPEAT) 1680.1a ^TM-2020 standards, jointly created by the US Environmental Protection Agency (EPA) and Institute of Electrical and Electronics Engineers (IEEE), the overall
F-GHG reduction rates achieved at all 12-inch wafer fabs of UMC and its subsidiaries were all higher than the standard threshold requirement of 75%.

UMC IEEE F-GHG Reduction Declaration

Intensity of F-GHGs Emissions

During its net-zero transition, UMC focuses on reducing fluorinated greenhouse gas (F-GHG) emissions from its manufacturing processes and lowering indirect emissions (Scope 2) arising from purchased electricity. UMC also conducts and implements a just transition assessment and response measures for potential impacts on employees, the value chain, and local communities. Recognizing that renewable energy is a key measure for achieving net zero—and that its adoption may generate broader and more material impacts on local society and the environment—UMC has further strengthened its just transition assessment for renewable power plants to ensure that carbon reduction benefits progress in parallel with social equity, local concerns, and environmental protection.

• Employees: UMC regularly plans and delivers training on climate-related topics and energy-saving/carbon-reduction practices to enhance employees’ awareness and capabilities regarding climate issues, thereby strengthening the organization’s climate resilience. However, in the short term, these efforts increase learning and adaptation pressures, as well as training requirements.
• Value chain: UMC has supported suppliers through a strategic, step-by-step approach to greenhouse gas (GHG) inventory and emissions management. Decarbonization measures help enhance corporate image, build trust in sustainable development, and further encourage customers, investors, and upstream/downstream supply chain partners to participate in emissions reduction. This, in turn, supports industry upgrading and creates green job opportunities.
• Communities: Promoting renewable energy in collaboration with energy suppliers can stimulate local economic development and create jobs in related industries. Given that the construction of renewable power plants may affect local residents, UMC encourages renewable energy suppliers to implement measures to mitigate negative impacts. These include establishing clear external communication and grievance/feedback channels regarding local livelihoods, construction noise, and traffic impacts; implementing pre-construction notification mechanisms; prohibiting nighttime construction to reduce disturbance; and, during construction, adopting traffic management procedures (avoiding peak hours, installing signage and deploying traffic guides, and planning alternative routes during road closures) to minimize impacts on local traffic. During subsequent plant operations, UMC also implements fisheries impact compensation measures, such as allocating fisheries compensation funds.

In order to lessen environmental impact of greenhouse effect and minimize energy consumption, UMC set company-wide carbon reduction goals and development plans through the Corporate Sustainability Committee, which coordinates and integrates energy saving and carbon reduction strategies and initiatives of various departments. Regular committee meetings are held to review progress. The Company continually introduces energy saving technologies and implements energy efficiency improvement programs in all facilities. In addition to its strategy of energy conservation, increasing energy efficiency, and expanding installation of renewables, UMC also promotes the implementation of energy management in its offices and common areas through activities, education, and training to cultivate a mindset and habit of energy conservation and GHG emission reduction among employees.

Note:

1. The statistics of calculation is based on electricity consumption per unit product by 2015 and the scope covers UMC.
2. CO₂ emissions are calculated using the latest local electricity coefficient. Taiwan: 0.474 kg CO₂e/KWh; Singapore: 0.402 kgCO₂e/KWh
3. The amount of natural gas saved through energy-saving measures is a theoretical calculation.
   Additionally, the calculation of carbon emissions is based on the emission factors for stationary and mobile combustion sources as specified in the Ministry of Environment's Greenhouse Gas Emission Factors General Description and Itemized Explanations.
   
4. The newly added improvement item was calculated based only on the 12-month performance. For the cross-year project, only the performance generated in 2025 was counted.

To diversify energy sources, UMC is actively installing renewable energy facilities in fabs. Solar energy system is a standard item that will be included in the design and construction of all new fabs. UMC Group joined RE100 as a member, becoming the second semiconductor wafer foundry in this international renewable energy initiative. The Company is committed to using 100% renewable energy by 2050, and has set progressive mid-/long-term goals. UMC intends to support the low-carbon energy transition through solid actions.

Renewable Energy Usage Target

In addition to continuously improving energy efficiency, the UMC Group also plans to use multiple energy sources, actively deploying on-site renewable energy, and lists solar energy systems as a standard part of design and construction project for new fabs. The power generation has increased for five consecutive years. The original plan to install 900 kW of solar PV in 2025 has been revised, with additional capacity to be consolidated into the 2026 plan for a total of approximately 2,500kW.
UMC Group had installed a solar photovoltaic system with a total peak capacity of approximately 14,000 kWp, with estimated annual power generation of about 15,500 MWh. However, solar photovoltaic generation is mainly affected by factors such as weather conditions. The figure of power generation is an estimated value rather than a fixed value. In 2025, electricity generated by the UMC Group‘s solar PV systems for self-consumption totaled 15,961 MWh. Since the end of 2024, all solar PV generation has been used for self-consumption, and the Group will continue to increase self-generation electricity to support clean energy.

Solar PV electricity generated for self-consumption